1. Field of the Invention
This invention relates to a novel platinum catalyst composition useful for the so-called hydrosilylation.
2. Description of the Prior Art
The reaction for adding an organosilicon compound having a .tbd.SiH radical in its molecule to an organic compound having an unsaturated double bond is known as the so-called hydrosilylation, and has been utilized for the synthesis of new organosilicon compounds.
In the hydrosilylation employed for the synthesis of organosilicon compounds, a variety of platinum catalysts have generally been used. As the platinum catalysts for such use, there have been known, for example, platinum supported on activated carbon (U.S. Pat. No. 2,970,150), chloroplatinic acid (U.S. Pat. No. 2,823,218), a platinum-organic compound complex (U.S. Pat. No. 3,159,601), a platinum-organofunctional polysiloxane complex (Japanese Patent Publication (KOKOKU) No. 63-19218 (1988)), etc.
Though the known platinum catalysts have the merit of being rich in reactivity by virtue of good activity for addition reaction, their high activity would cause rearrangement of a terminal unsaturated double bond of the organic compound used as a reactant in the hydrosilylation. As a result of the rearrangement, isomeric raw materials with poor reactivity may remain as unreacted material in the reaction system, or isomers of the intended organosilicon compound may be by-produced in large quantities, leading to an unfavorably lower yield of the desired product. Further, the isomeric raw materials are difficult to reuse, even if recovered. Moreover, the by-produced isomers are very difficult to separate for purification from the intended organosilicon compound, due to the similarity in chemical structure.